The present invention relates to an apparatus and a method for transdermal or subcutaneous delivery of a medical or bioactive solution.
Topical application, local or external, is the mainstay treatment in skin diseases because of its ease and reduced systemic side effects. However it has been shown in various studies that only 1% of the drug gets absorbed inside regardless of the vehicle used. The reason for that are that the skin is protected by keratinous dead layers that wards of germs and insulates the inner body from the outside environment. This means that more frequent applications or prolonged duration of treatment are needed to reach desired results. Furthermore most of the drug gets wasted without even reaching its target.
Another reason for the reduced efficacy of local or external treatment is the chance of it being rubbed off or removed by the patient or others. To bypass the outside barrier, occasionally intralesional injections are given. These are only given by trained medical personnel and requires experience to know the proper depth of treatment and is usually painful if many injections are needed. Another problem is that an injector can reach only a tiny part with each injection. If he is to treat the whole area he has either to inject large amounts of fluid per injection or introduce the needle many times before it dulls and hurts even more. Another problem is that even if an injector performs multiple injections it is hard to control the depth and the volume injected each time he injects. The last statement is especially true in curved surfaces. It would also take a long time to finish the treatment.
A method of treatment known as mesotherapy is routinely done in clinics to treat various skin diseases by injecting through an automated pulsating needle which is moved by the injector manually from one site to another as the needle emerges back and forth. The problem with such treatment is that the treatment doesn't take into account the changing topography of the skin with the treatment given at varying depths and it's impossible to correctly space the injections. Additionally only a tiny part of the skin gets treated each time. Since one of the main indications of mesotherapy is liposculpturing, injecting at various depths may predispose to irregularities later on.
Chemical peels are compounds used to exfoliate the skin in a controlled manner to treat various skin diseases. They include but are not restricted to trichloroacetic acid, phenol, glycolic and salicylic acid peels. After prepping the skin, the peel of choice is applied on the skin evenly with the use of gauzes in one or more coats until the end point is reached. The patient goes home anticipating the healing phase to last anywhere from days to weeks depending on the peel. During this healing phase, skin starts to peel off, and new skin formation takes place as the redness and oozing fades away. This phase is known as downtime period.
Aging skin is characterized by wrinkling, rough texture and uneven pigmentation. These characteristics are associated with decreased Elastin, collagen, epidermal atrophy, cellular atypia, and dysplasia. These changes presumably result from DNA mutation and other cellular and protein damage. The consequence is abnormal collagen, Elastin, and ground substance breakdown. Cumulative sun exposure and smoking are some of the causes of photodamaged skin.
The wounds created by these acids stimulate the skin to synthesize collagen and induce peeling of the epidermis leading to skin regeneration. The result is a healthier skin with improved texture, smoothening of wrinkles, tightening of skin and amelioration of pigmentary changes. Therefore chemical peels are used to treat signs of aging and photo-damage such as wrinkles and precancerous lesions. It has also been used for various diseases such as melasma, acne, dyschromias, epidermal growths such as wart and milia.
Depending on the depth of these peels, they have been classified into superficial, medium and deep peels. When the peel extends to only the epidermis they are known as superficial peels. Whereas medium depth peels extend into upper reticular dermis and deep peels into mid reticular dermis. The type of the peel, its concentration, the duration of treatment and other factors determine the depth of the peel.
As with any medical procedure, chemical peels may be associated with complications. This is especially true with deep peels with all of the epidermis and a huge portion of the dermis damaged leaving the skin vulnerable during the healing phase. A common complication seen in phenolic deep peels is post inflammatory hypopigmentation. Scarring, post inflammatory hyperpigmentation, persistent erythema and delayed healing are other examples. Furthermore, since the deep peels produce deep oozing wounds, there is a higher rate for infection and a long downtime and the patient may wait weeks to months before he or she is completely healed.
Due to these complications, medium and deep peels, such as phenol and trichloroacetic acid 35% and higher are falling out of favour as the treatment of choice for skin rejuvenation. Therefore it would be desirable to have a method by which a peel's rejuvenating potential is maximized without significant complications and with less downtime. Another reason for the unpredictable results seen with chemical peels given in a traditional way is that the gauze that is used to apply the acid on the skin is applied with varying pressures depending on how firm is it applied and how much acid is left in the gauze before reapplication. This is different from one doctor and another and even in the same patient when curved surfaces such as the neck is met, making the treatment hard to standardize with the uneven application.
Dermarollers have been used to induce wounds that stimulate collagen deposition, but only have modest results since it is not accompanied by injecting materials into the skin. Some practitioners would apply the solutions onto the skin before using a dermaroller hoping that the needle would transfer the solution inside the skin but only a fraction of that reaches and only superficially in a non standardized way. Furthermore the holes induced by the dermaroller tend to close by coagulation limiting any spread of solution.
It would be desirable to have a device that tackles the above problems and can be used to deliver bioactive substances, drugs or cosmeceuticals to the skin uniformly.
According to the invention, the above mentioned problems are at least partially solved by an apparatus for transdermal or subcutaneous delivery of a bioactive solution, including a plurality of needles fixed on a needle carrier in a spaced apart relationship and projecting from the needle carrier, each needle having a tip zone adapted to receive an amount of bioactive solution from a reservoir coupled to the needle carrier and to deliver the bioactive solution upon penetrating a skin.
Advantageously, the tip zone is hollow. In some embodiments, the reservoir is pressurized. The problems of the invention are at least partially solved by a method of subcutaneously or transdermally delivering a bioactive solution, by using an apparatus according to the invention, applying or rolling the apparatus on the skin, thereby delivering an amount of solution each time a needle penetrates the skin. According to the invention, it is advantageous that the solution comprises at least one of the following substances: phenol, trichloroacetic acid, glycolic acid, salicylic acid, jessner's peel, aminolevulinic acid, methyl aminolevulinate, botox, corticosteroid, filler.